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use {
    crate::{check_program_account, error::TokenError, instruction::TokenInstruction},
    num_enum::{IntoPrimitive, TryFromPrimitive},
    solana_program::{
        instruction::{AccountMeta, Instruction},
        program_error::ProgramError,
        pubkey::Pubkey,
    },
    std::convert::TryFrom,
};

/// Default Account State extension instructions
#[derive(Clone, Copy, Debug, PartialEq, IntoPrimitive, TryFromPrimitive)]
#[repr(u8)]
pub enum RequiredMemoTransfersInstruction {
    /// Require memos for transfers into this Account. Adds the MemoTransfer extension to the
    /// Account, if it doesn't already exist.
    ///
    /// Accounts expected by this instruction:
    ///
    ///   0. `[writable]` The account to update.
    ///   1. `[signer]` The account's owner.
    ///
    ///   * Multisignature authority
    ///   0. `[writable]` The account to update.
    ///   1. `[]` The account's multisignature owner.
    ///   2. ..2+M `[signer]` M signer accounts.
    ///
    Enable,
    /// Stop requiring memos for transfers into this Account.
    ///
    /// Fails if the account does not have the extension present.
    ///
    /// Accounts expected by this instruction:
    ///
    ///   0. `[writable]` The account to update.
    ///   1. `[signer]` The account's owner.
    ///
    ///   * Multisignature authority
    ///   0. `[writable]` The account to update.
    ///   1. `[]`  The account's multisignature owner.
    ///   2. ..2+M `[signer]` M signer accounts.
    ///
    Disable,
}

pub(crate) fn decode_instruction(
    input: &[u8],
) -> Result<RequiredMemoTransfersInstruction, ProgramError> {
    if input.len() != 1 {
        return Err(TokenError::InvalidInstruction.into());
    }
    RequiredMemoTransfersInstruction::try_from(input[0])
        .map_err(|_| TokenError::InvalidInstruction.into())
}

fn encode_instruction(
    token_program_id: &Pubkey,
    accounts: Vec<AccountMeta>,
    instruction_type: RequiredMemoTransfersInstruction,
) -> Instruction {
    let mut data = TokenInstruction::MemoTransferExtension.pack();
    data.push(instruction_type.into());
    Instruction {
        program_id: *token_program_id,
        accounts,
        data,
    }
}

/// Create an `Enable` instruction
pub fn enable_required_transfer_memos(
    token_program_id: &Pubkey,
    account: &Pubkey,
    owner: &Pubkey,
    signers: &[&Pubkey],
) -> Result<Instruction, ProgramError> {
    check_program_account(token_program_id)?;
    let mut accounts = vec![
        AccountMeta::new(*account, false),
        AccountMeta::new_readonly(*owner, signers.is_empty()),
    ];
    for signer_pubkey in signers.iter() {
        accounts.push(AccountMeta::new_readonly(**signer_pubkey, true));
    }
    Ok(encode_instruction(
        token_program_id,
        accounts,
        RequiredMemoTransfersInstruction::Enable,
    ))
}

/// Create a `Disable` instruction
pub fn disable_required_transfer_memos(
    token_program_id: &Pubkey,
    account: &Pubkey,
    owner: &Pubkey,
    signers: &[&Pubkey],
) -> Result<Instruction, ProgramError> {
    check_program_account(token_program_id)?;
    let mut accounts = vec![
        AccountMeta::new(*account, false),
        AccountMeta::new_readonly(*owner, signers.is_empty()),
    ];
    for signer_pubkey in signers.iter() {
        accounts.push(AccountMeta::new_readonly(**signer_pubkey, true));
    }
    Ok(encode_instruction(
        token_program_id,
        accounts,
        RequiredMemoTransfersInstruction::Disable,
    ))
}